Magnetic stud finder



April 19, 1960 R. D. BRAY MAGNETIC STUD FINDER Filed Feb. 15, 1957 I c JZ RICA/42D ,D. fleny,

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United States Patent MAGNETIC STUD FINDER Richard D. Bray, Long Beach, Calif.

Application February 15, 1957, Serial No. 640,381

6 Claims. (Cl. 324-41) The present invention relates generally to carpentry and household accessories, and more particularly to a magnetic stud finder.

A major object of the present invention is to provide a novel and improved stud finder by which hidden pieces offerrous material such as nails, screws, or the like disposed in a wall structure may be accurately located, and one that is completely corrosion resistant and will operate satisfactorily, even after prolonged exposure to the weather.

Another object of the invention is to provide a stud finder that is light in weight, of simple mechanical structure, and is so compact that it may be conveniently carried in a shirt or coat pocket, or may be suspended by a string or cord from the operators neck, or affixed to a portion of his garments.

Another object of the invention is to supply a device of the character described in which the ferrous magnetic needle associated therewith is completely sheathed in a polymerized resinous material that protects the needle from rust or corrosion.

Still another object of the invention is to furnish a stud finder in which all of the components thereof except the ferrous needle are adapted to be injection molded.

A still further object of the invention is the provision of a magnetic stud finder in which the ferrous needle is completely enclosed within a plastic sheath whereby the external needle surface need not be highly finished and polished as is necessary with presently available magnetic stud finders.

Yet another object of the invention is to provide a device of the character described in which the needle is free to rotate through a full 360 whereby it cannot be damaged by inadvertent contact with the side walls of the case, and one which due to the nature of the materials forming same, is adapted to have the magnetic needle enveloped in a colored plastic material that contrasts to that of the back of the instrument against which it is seen.

These and other objects and advantages of the invention will become apparent from the following descrip-' tion of a preferred form of the invention and from the accompanying drawings illustrating that form, in which:

Figure 1 is a perspective view of the stud finder shown as used in locating a nail or other ferrous object embedded in a stud situated within a wall;

Figure 2 is a top plan view of the stud finder after finding a hidden nail, showing the magnetic needle in dotted line in coaxial alignment with a hidden nail or other ferrous object, and showing the needle prior to such location in phantom line;

Figure 3 is a vertical cross-sectional view of the device taken on line 33 of Figure l; and

Figure 4 is a perspective view of the needle and the two halves of the sheath shown prior to insertion of the needle to completely enclose same.

Referring to Figures l and 3 of the drawings for the general arrangement of the invention, it will be seen to include a housing A that is preferably formed from a first trapezoidal cup-shaped member B and a second B but with a prime affixed thereto.

trapezoidal cup-shaped member C that interlock at their abutting edges to define a completely enclosed space D. Housing member B, as can best be seen in Figure 3, is provided with an inwardly extending journal block E that is in transverse alignment with a second journal block F formed on the interior surface of the second housing member C. An elongate bar G of ferrousmaterial that is adapted to be permanently magnetized is provided and is completely enclosed between a first half sheath portion H and a second half sheath portion J which are bonded at their abutting edges. A conical stub shaft L extends outwardly from substantially the center of sheath portion H and a conical stub shaft M also extends outwardly from substantially the center of sheath portion J. The pointed extremities of shafts L and M are pivotally supported in recesses 10 and 12 that are formed on the adjacent end portions of journal blocks E and F respectively.

Housing member B (Figure 1) includes a transparent sheet 14 that is preferably trapezoidal in shape defined by two outwardly diverging edges 16 and 18 which terminate in end edges 20 and 22 respectively. A continuous skirt 24 extends from edges 16, 18, 20 and 22, which skirt is disposed substantially normal to sheet 14. A continuously extending recess 26 is formed on the interior edge portion of skirt 24. Housing member C is identical in shape and configuration to housing member B and corresponding portions thereof are identified by the same numerals as used with housing member Housing member C has a skirt 24 extending therefrom which is provided with a continuously extending rib 28 on the extremity thereof that is adapted to be slidably inserted within the confines of groove 26. Adjacently disposed tongues 30 and 30 project outwardly from the narrow ends of first and second skirts 24 and 24 repectively. Transverse coaxially aligned bores 32 and 32' are formed in tongues 30 and 30' through which bores a string or cord (not shown) may be extended from which the invention may be suspended from the neck or a suitable portion of the users clothing.

The first housing member B may be formed of any one of the numerous transparent synthetic resinous materials that are commercially available for molding, and the second housing portion C may also be formed from such a resinous material, but one that is opaque and preferably brightly colored.

The first half sheath portion H and second half sheath portion J are semi-cylindrical in shape, the ends ofwhich are closed with identical semicircular end pieces 34 and 34 respectively. Sheath portion H and sheath portion I are adapted to snugly engage the exterior surface of the cylindrical magnetic bar G, as shown in Figures 3 and 4. When so disposed, the edges of these sheath portions are in abutting contact. The free edges of the first and second sheath portions are bonded to one another by any one of the conventional techniques now employed for such purposes, with the magnetic bar G being completely enclosed within the confines thereof. It will be particularly noted that when sheath portions H and I completely enclose bar G as described, the stub shafts L and M project outwardly therefrom in opposing directions to permit the enclosed bar G to be freely and pivotally supported from the journal blocks E and F as shown in Figure 3.

The polymerized resinous material employed in the fabrication of sheath portions H and J is preferably brightly colored in a color that is in distinct contrast to housing member C whereby the position of bar G will at all times be clearly visible against this contrasting background. The visibility of the enclosed bar is further increased by providing a recessed polished window 38 in the first housing member B, as can best be seen in Figures 1 and 3.

The components above described are easily assembled to provide the present invention by simply inserting the sheathed magnetic bar G within the confines of housing members B and C and locking these members together by inserting the tongue 28 into groove 26 as shown in detail in Figure 3.

In use, the operation of the stud finder described above is extremely simple. When it is desired to find a stud, the finder is simply grasped by the hand and moved along a wall. As the invention approaches a hidden nail 40 holding a Wallboard 42 to a stud 44, the pivotally sup ported magnetic bar G begins to pivot and will move from one of the positions shown in phantom line in Figure 2 to the position shown in dotted line in the same figure wherein the bar is normally disposed to the stud when the needle is in alignment with the nail 40 embedded therein. The usefulness of the invention will be self-evident due to the fact that the nails 40 are normally concealed by wallboard 42 that is covered with a layer of plaster 46.

Although the invention herein shown and described is fully capable of achieving the objects and providing theadvantages as herein set forth, it is to be understood that it is merely illustrative of the presently preferred embodiment thereof and that I do not mean to limit myself to the details of construction as herein described and shown other than as defined in the appended claims.

I claim:

1. In a corrosion resistant stud finder comprising: an-

elongate magnetic bar; first and second half sheath portions formed of a polymerized resin that completely envelop said bar and snugly engage same, which sheath portions have edge surfaces that may be placed in abutting contact; first means that bond said edge surfaces together to hold said first and second sheath portions in said enveloping position; first and second stub shafts formed of a polymerized resin that extend outwardly in opposite directions from said first and second sheath portions respectively; first and second elongate cup-shaped housing portions formed of a polymerized resin, which housing portions define edge surfaces that can be placed in abutting contact, with said housing portions when said edge surfaces thereof are so disposed defining a confined space within the interior thereof; second means that bond said edge surfaces of said first and second housing portions to one another; and first and second journal blocks formed of a polymerized resin supported from the interior surfaces of said first and second housing portions that pivotally support said first and second stub shafts to permit 360 rotation of said sheathed bar in said confined space and in a fixed plane relative to said housing portions.

2. In a stud finder as defined in claim 1 wherein said first and second shafts are of conical configuration, said first and second journal blocks have conical recesses formed therein that are complementary to at least the outer portions of said shafts, and said outer portions of said shafts are pivotally supported in said recesses.

3. In a stud finder as defined in claim 1 wherein said first and second housing portions are of elongate tapered configuration and said journal blocks are disposed adjacent the widest ends thereof, with a part of said first housing portion above said sheathed bar being polished.

and transparent to permit clear vision of said sheathed bar.

4. in a stud finder as defined in claim 3 wherein said first and second sheath portions are of a first bright color, and said second housing portion is of a second bright color that contrasts to said first color to permit easy visual detection of pivotal movement of said sheathed bar relative to said second housing portion.

5. A corrosion resistant magnetic indicating device that is capable of being pivotally supported between two spaced, axially aligned journal blocks comprising: an elongate magnetic bar; two semi-cylindrical sheaths formed of a polymerized resinous material that are adapted to completely envelop said bar and snugly engage same, said sheaths when so engaging said bar having edge surfaces that are in abutting contact; means that bond,

said abutting edge surfaces together; and two stub shafts extending outwardly in opposite directions from said sheaths and being capable of pivotally engaging said journal blocks.

6. A corrosion resistant magnetic indicating device as defined in claim 5 wherein said stub shafts are of conical configuration.

References Cited in the file of this patent UNITED STATES PATENTS 1,035,973 Kraemer Aug. 20, 1912 2,687,577 Pallotti Aug. 31, 1954 2,723,369 Brummett Nov. 8, 1955 

